BY DR. KLEIN. 129 



right, the omentum, which usually lies on the anterior surface 

 of the stomach, is carefully brushed in situ, from below up- 

 wards, with a camel-hair pencil, moistened with peritona-al 

 liquid. Half percent, solution of silver is then allowed to drop 

 over the surface from a capillary pipette, until the membrane 

 is distinctly turbid. It must then be gently streamed with 

 water, and removed along with the stomach, and placed in 

 water exposed to the light. Portions of the membrane are 

 then cut out, and covered in glycerin -with the pencilled surface 

 upwards. In preparations so obtained, an abundant network of 

 lymphatics presents itself. In addition to this, there are cer- 

 tain parts of the surface in which the lymphatic cells are 

 crowded together in patches. It is seen, in parts where the 

 endothelium has not been completely removed, that the cells 

 which lie immediately underneath it project so as to form 

 pseudo-stomata, and in other respects stand in the same rela- 

 tion to it and to those which line the lymphatic capillaries, as 

 on the surface of the diaphragm. It is also seen that in some 

 of the patches there are lymph sinuses which communicate with 

 the surface by true stomata. As was indicated in Chapter II., 

 the endothelium which covers these lymphatic patches, particu- 

 larly that which surrounds stomata and pseudo-stomata, differs 

 from that of the general surface, by the smaller size, polyhedral 

 form, and granular appearance of the elements. The same 

 tissue also presents itself in the form of tracts alongside of the 

 larger vessels. 



In the dog, guinea-pig, and cat, these tracts are particularly 

 well developed along the large vessels which are to found in 

 the trabeculse of the membrane. Connected with these, there 

 are nodular structures which project more or less from the 

 surface. Both the tracts and the nodules consist of aggrega- 

 tions of lymphatic cells close together, richly supplied with 

 bloodvessels, and covered with an endothelium which has the 

 same characters as that which covers the patches. In the 

 neighborhood of the tracts, lymphatic vessels are usually to be 

 seen on one or both sides, which often communicate by cross 

 branches, and stand in (he same relation to the lymphatic 

 elements as in the patches. The canaliculi of the tracts and 

 nodules sometimes contain what appear to be young cells, 

 which, from what has been observed in pathological conditions 

 of the structure, must be regarded even in the normal state as 

 to a great extent offsprings of the endothelial elements. 



Mesentery. In the mesentery treated in the same way as 

 that above described, in addition to the lymphatic vessels 

 which proceed from the intestine, numerous lymphatics with 

 dilatations (sinuses) can be demonstrated. The canaliculi with 

 which they are surrounded and in communication, pervades 

 the ground-substance of the mesentery in every direction. In 

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